A decision analysis comparing three strategies for peritoneal lavage cytology testing in staging of gastric cancer in China.

Background Positive peritoneal cytology (PCY) indicates metastasis (M1) in gastric cancer (GC) patients; both the American and Chinese guidelines recommend laparoscopic peritoneal lavage (LPL) for cytology. However, relatively high costs impair the widespread use of LPL in some resource-limited regions in China, and the cost-effectiveness of PCY testing remains unclear. Therefore, we performed a decision analysis to evaluate the cost-effectiveness of PCY testing by comparing the guideline-recommended intraoperative LPL, a newly proposed preoperative percutaneous peritoneal lavage (PPL), and a third strategy of exploratory laparotomy with no cytology testing (ELNC) among GC patients. Methods We developed a decision-analytic Markov model of the aforementioned three strategies for a hypothetical cohort of GC patients with curative intent after initial imaging, from the perspective of Chinese society. We estimated costs, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratios (ICERs) as primary outcomes; we also conducted one-way and probabilistic sensitivity analyses to investigate the model's robustness. Results We found that ELNC was dominated (i.e., more expensive and less effective) by PPL and LPL. LPL was the most cost-effective method with an ICER of US$17,200/QALY compared to PPL, which was below the Chinese willingness-to-pay (WTP) threshold of US$29,313 per QALY gained. In sensitivity analyses, PPL was more likely to be cost-effective with a lower WTP threshold. Conclusions Cytology testing through either LPL or PPL was less expensive and more effective than ELNC among GC patients. Moreover, LPL was the most cost-effective modality at the current WTP threshold, while PPL could potentially be cost-effective in lower-income areas.